Marburg and Ebola are filoviruses that cause hemorrhage, multiple organ failure, and high mortality rates. Diagnosis is with enzyme-linked immunosorbent assay, PCR, or electron microscopy. Treatment is supportive. Strict isolation and quarantine measures are necessary to contain outbreaks.

Marburg and Ebola viruses are filoviruses that are distinct from each other but that cause clinically similar diseases characterized by hemorrhagic fevers and capillary leakage. Ebola virus infection is slightly more virulent than Marburg virus infection.

Reston Ebola virus (which is present in Asia but does not cause disease in humans)

Most previous outbreaks of Marburg and Ebola virus infections have originated in sub-Saharan Central and West Africa. Past outbreaks have been rare and sporadic; they have been contained partly because they have occurred in isolated areas. Spread to other areas, when it occurs, has usually resulted from travelers returning from Africa. However, in 1967, a small Marburg hemorrhagic fever outbreak occurred in Germany and Yugoslavia among laboratory workers who had been exposed to tissues from imported green monkeys.

In December 2013, a large Ebola virus outbreak began in rural Guinea (West Africa), then spread to densely populated urban regions in Guinea and to neighboring Liberia and Sierra Leone. It was first recognized in March 2014. It has so far involved thousands of people and has a mortality rate of about 59%. Infected travelers have spread Ebola virus to Europe and North America.

Transmission

Most index cases involve exposure to nonhuman primates in sub-Saharan Africa. The vector and reservoir are not known precisely, although the Marburg virus has been identified in bats, and cases have occurred in people exposed to bats (eg, in mines or caves). Ebola virus outbreaks have been linked to consumption of meat from wild animals in affected areas (bush meat) or soup made from bats. Ebola and Marburg virus infections have also occurred after handling tissues from infected animals.

Filoviruses are highly contagious. Human-to-human transmission occurs via skin and mucous membrane contact with body fluids (saliva, blood, vomit, urine, stool, sweat, breast milk, semen) of an infected symptomatic person or rarely a nonhuman primate. Humans are not infectious until they develop symptoms. Symptoms and signs persist in surviving patients for as long as it takes to develop an effective immune response. Typically, surviving patients eliminate the virus entirely and no longer transmit the virus. Semen can transmit infection for up to 7 mo in contrast to other body fluids.

Aerosol transmission has been postulated; however, if it occurs, it is probably rare.

Real-world transmission is mainly human-to-human, resulting from close contact with the blood, secretions, other body fluids, or organs of infected people. Burial ceremonies in which mourners have direct contact with the deceased have played an important role in transmission of infection.

Symptoms and Signs

After an incubation period of 2 to 20 days, fever, myalgia, and headache occur, often with abdominal pain, nausea, and upper respiratory symptoms (cough, chest pain, pharyngitis). Photophobia, conjunctival injection, jaundice, and lymphadenopathy also occur. Vomiting and diarrhea may soon follow. Delirium, stupor, and coma may occur, indicating CNS involvement.

Hemorrhagic symptoms begin within the first few days and include petechiae, ecchymoses, and frank bleeding around puncture sites and mucous membranes. A maculopapular rash, primarily on the trunk, begins around day 5.

Severe hypovolemia can develop, resulting from

Extensive fluid loss due to diarrhea and vomiting

Capillary leakage, resulting in hypoalbuminemia and loss of fluid from the intravascular space

During the 2nd wk of symptoms, either defervescence occurs and patients begin recovery, or patients develop fatal multiple organ failure. Recovery is prolonged and may be complicated by recurrent hepatitis, uveitis, transverse myelitis, and orchitis. Mortality ranges from 25 to 90% (higher with Ebola virus infection, averaging about 59%).

Diagnosis

Evaluation and testing per the Centers for Disease Control and Prevention (CDC) guidelines

Marburg or Ebola virus infection is suspected in patients with bleeding tendencies, fever, other symptoms consistent with early Ebola virus infection, and travel from endemic areas. The CDC has issued an algorithm and guidelines for evaluating travelers returning from endemic areas (see
Algorithm for Evaluation of the Returned Traveler
and
Think Ebola: Early recognition
). A similar approach can be used if Marburg virus is suspected.

The WHO has also issued guidelines regarding the 2014 Ebola outbreak in West Africa (
WHO Statement).

Cases should be discussed with public health authorities, who can assist in all facets of management, including

Deciding whether to pursue the diagnosis

Arranging transport of samples for testing

Treatment, including transport to selected centers and, when indicated, use of novel therapies

Treatment

No effective antiviral therapy exists. Treatment is supportive and includes the following:

Maintenance of blood volume and electrolyte balance

Replacement of depleted coagulation factors

Minimization of invasive procedures

Treatment of symptoms, including use of analgesics

Drugs are being tested, some under expedited procedures, but none have yet been proved effective and safe.

Prevention

Several vaccines and antiviral drugs are currently in development but are unlikely to be available imminently.

To prevent spread, symptomatic patients with possible Ebola or Marburg virus infection must be isolated in dedicated containment facilities. Standard intensive care units (ICUs) in public hospitals are not suitable. Special containment facilities provide for total control of fluid effluent and respiratory products. The number of such centers is increasing in response to the urgency of the situation.

Staff members in contact with patients must be completely covered in protective suits with internal containment of respiratory gases. Trained staff members must be available to help those in contact with patients remove the protective clothing. Protocols for donning and removing mask, goggles or face shields, gown, and gloves must be followed (see the CDC's
Sequence for Donning Personal Protective Equipment
).

FRIDAY, June 26, 2015 (HealthDay News) -- A new rapid-detection test that diagnoses Ebola within minutes could improve treatment of the virus and help health care workers contain outbreaks, according to research published online June 25 in The Lancet .
Nira Pollock, M.D., associate medical...

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